said by bbear2:The 3801HGV is a VDSL modem that cannot be bridged. If you want to run a router behind the 3801, connect it to one of the LAN ports and then put that device in DMZ+ mode in the modem firewall.
I'm not sure you can restrict the BW by 8M vs. 4M, but there is something call QOS that will allow you to give different priorities to different devices/messages. I'm not that familiar with the 2Wire RG, Model 3801HGV, but a quick look as the datasheet »search.yahoo.com/r/_ylt=A0oGdVs4···3801.pdf did not show any QOS mention.
I'm not sure if you can put your modem into bridge mode, but if you can, then you can purchase a router that does QOS that is better suited for what you are trying to do. There are many out there, but for example the D-Link DIR-657, DIR-827, DIR-857. Netgear and Cisco make some nice ones too.